using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;

namespace TestingGame
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch SpriteBatch;
        Texture2D maskingTexture;
        Texture2D spriteTexture;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            // TODO: Add your initialization logic here

            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            SpriteBatch = new SpriteBatch(GraphicsDevice);

            // TODO: use this.Content to load your game content here
            spriteTexture = Content.Load<Texture2D>("SandTextureTile");
            maskingTexture = Content.Load<Texture2D>("mask");

            Location = new Rectangle(20, 20, 64, 64);
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();

            // TODO: Add your update logic here

            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        Rectangle Location;
        protected override void Draw(GameTime gameTime)
        {
            graphics.GraphicsDevice.Clear(Color.CornflowerBlue);

            // Set states to set the stencil buffer to mask the sprites
            GraphicsDevice.RenderState.StencilEnable = true;
            GraphicsDevice.RenderState.StencilFunction = CompareFunction.Equal;
            GraphicsDevice.RenderState.StencilPass = StencilOperation.Increment;

            GraphicsDevice.RenderState.ReferenceStencil = 0;
            GraphicsDevice.RenderState.DepthBufferWriteEnable = false;
            GraphicsDevice.RenderState.ColorWriteChannels = ColorWriteChannels.None;

            // Start the sprite batch to draw the mask
            SpriteBatch.Begin(SpriteBlendMode.AlphaBlend);
            SpriteBatch.Draw(maskingTexture, Location, Color.White);
            SpriteBatch.End();

            // Set some states to allow the stencil buffer to mask the tiles
            GraphicsDevice.RenderState.DepthBufferWriteEnable = true;
            GraphicsDevice.RenderState.ColorWriteChannels = ColorWriteChannels.All;
            GraphicsDevice.RenderState.StencilPass = StencilOperation.Keep;

            // Draw sprites
            SpriteBatch.Begin(SpriteBlendMode.AlphaBlend, SpriteSortMode.Immediate, SaveStateMode.None);
            SpriteBatch.Draw(spriteTexture, Location, Color.White);
            SpriteBatch.End();

            // End the stencil buffer
            GraphicsDevice.RenderState.StencilEnable = false;

            base.Draw(gameTime);
        }
    }
}
